Waste-to-energy plants: turning trash into electricity, but at what cost?
New Delhi (The Uttam Hindu): An investigative report has raised concerns about Delhi's approach to waste management and its serious implications for public health, particularly in the context of the already hazardous air quality in the National Capital Region (NCR), which has been further exacerbated by farm fires and other environmental factors. The city's waste-to-energy (WTE) incinerators, hailed as a technological solution to the growing garbage crisis, have come under scrutiny for their environmental and public health impacts. These plants, designed to convert municipal solid waste into electricity, involve a complex interplay of technology, environmental considerations, and urban planning challenges.
The Science Behind Waste-to-Energy Incineration
In principle, the science behind WTE incineration is simple: municipal solid waste (MSW) is burned at high temperatures to generate heat, which produces steam. This steam powers turbines connected to generators that produce electricity. However, in practice, the process is far more complicated and presents several environmental concerns. The process starts with waste collection and transportation to the incineration facility, where the waste is sorted to remove recyclables and hazardous materials. The remaining waste is then fed into the incinerator, where temperatures can reach up to 1000°C. As the waste burns, gases are produced and are carefully controlled and filtered to reduce harmful emissions. The heat generated is used to boil water, creating steam that powers turbines.
The Hidden Problem: Toxic Ash
While this process does generate electricity, it also produces two types of ash: bottom ash and fly ash. Bottom ash, which makes up about 20-30% of the original waste volume, is the residue left after combustion. Fly ash, which is captured by pollution control devices, is far more concerning due to its high concentration of toxic substances. Both types of ash require proper handling and disposal in scientifically managed landfills to avoid environmental contamination. Delhi's first WTE plant, located in Okhla and commissioned in 2010, was designed to process 2,000 tons of garbage per day. However, it has been the subject of ongoing controversy. Public protests over environmental and health concerns were validated by a report from the Central Pollution Control Board (CPCB), which found dangerously high levels of dioxins and furans in emissions—exceeding permissible limits by 800-900%. These findings have raised significant health concerns for nearby residents.
India’s Growing Waste Problem
The push for WTE incinerators in Delhi comes amid India’s rapidly escalating waste generation. According to a 2021 report by NITI Aayog, the average per capita daily solid waste generation in 28 major Indian cities is 0.39 kg, with some cities producing as much as 0.99 kg per person per day. Projections show that urban areas will generate 165 million tons of municipal solid waste annually by 2031, with the figure rising to an alarming 436 million tons by 2050. While WTE incinerators present a potential solution to manage this increasing waste and generate energy, they come with significant drawbacks. Critics argue that these facilities discourage waste reduction and recycling efforts, while contributing to air pollution and other health hazards. The high levels of toxic emissions, particularly in densely populated areas like Delhi, remain a critical concern. As Delhi struggles with its waste management challenges, the debate over the use of WTE incinerators rages on. Striking a balance between efficient waste disposal and safeguarding public health and the environment continues to be a difficult task for policymakers and urban planners.
